74,983 research outputs found
Duck fleas as evidence for eiderdown production on archaeological sites
Acknowledgements This project was undertaken as part of my doctoral studies funded by the Commonwealth Scholarship Commission (CACR-2009-39) in the United Kingdom. I would like to thank my supervisors Karen Milek and Andrew Dugmore for their help and support. I also wish to thank Jónas Helgason, his son Alexius Jónasson and Baldur Vilhelmsson for kindly having allowed access to the eiderdown stores and workshops at Æðey and Vatnsfjörður and for having provided assistance when needed. I would like to thank Fornleifastofnun Íslands for supporting my fieldwork at Vatnsfjörður, as well as Paul Ledger and Garðar Guðmundsson for their help during fieldwork. I am especially grateful to Richard Marriott for his invaluable help with flea identifications and for lending me reference material. Erling Ólafsson and Jan Klimaszewski also helped with the beetle identifications. Consultation of the BugsCEP database (Buckland and Buckland, 2006) aided the redaction of this paper.Peer reviewedPostprin
Liver fluke infections in cattle and sheep
The trematode, Fasciola hepatica, is a cosmopolitan parasite of temperate regions that can infect a wide variety of wild and domestic mammalian species, including man. Host-responses differ amongst different species and this article focuses on the contrast between cattle and sheep, the two classes of livestock in which fasciolosis assumes the greatest economic importance. In the sheep, acute fasciolosis resulting from parenchymal damage to the liver and haemorrhage caused by migrating juvenile flukes is a severe and potentially fatal disease. In contrast, the parenchymal stages have limited effects in cattle and the acute form of the disease is extremely rare. Though there is no evidence for a functional, acquired immune response to Fasciola hepatica, cattle provide a less hospitable environment, probably due to the profound changes in parasitised bile ducts, which render them as unsuitable habitats for feeding fluke. Consequently, in untreated cattle, many liver fluke die within 18 months of infection, though some can survive for 2 years or more. In the sheep, essentially, the fluke can live as long as the sheep; up to 11 years has been reported. These differences lead to the need for different treatment approaches in cattle and sheep with respect to juvenile fluke, but do also provide some opportunities for novel control approaches, based on the relative tolerance of cattle and their ability to limit parasitic damage to the liver parenchyma
Grassland management and helminth control on cattle farms
Farmers manage their pastures and grazing animals primarily to ensure that swards provide adequate, quality nutrients to support animal performance, but it is also possible to provide useful levels of parasite control without compromising production. On cattle only farms the easiest options for the control of parasitic gastroenteritis in young cattle revolve around the avoidance of high risk pastures from July onwards. On many farms, silage/hay aftermaths that have not been grazed by cattle for 12 months or more can provide low risk fields on which cattle can thrive with minimal reliance on anthelmintics
Guiding Premises and Implementing Strategies for Transmational Leadership in the 21st Century
Theta Graph Designs
We solve the design spectrum problem for all theta graphs with 10, 11, 12, 13, 14 and 15 edges
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